1. Field of the Invention
The present invention relates to a bovine group I phospholipase A.sub.2 receptor; a structural gene of a bovine group I phospholipase A.sub.2 receptor; a bovine group I phospholipase A.sub.2 receptor encoded by the structural gene; an expression vector having the structural gene; a transformant having the expression vector; and a method for producing a bovine group I phospholipase A.sub.2 receptor using the transformant.
2. Description of the Related Art
Phospholipase A.sub.2 (hereinafter referred to as PLA.sub.2 ; EC 3.1.1.4) is a lipolytic enzyme for hydrolyzing a 2-acyl ester bond in 3-sn-phosphoglyceride and is known to be present in mammalian pancreas, snake venom and the like. PLA.sub.2 which is known in the art can be classified into a high molecular weight intercellular type and a low molecular weight secretion type. The low molecular weight secretion type PLA.sub.2 are further classified into two groups: PLA.sub.2 -I and PLA.sub.2 -II. PLA.sub.2 -I is present in mammalian pancreas and the like. PLA.sub.2 -I in the pancreas is one of the digestive enzymes secreted in pancreatic juice, and is generally present as a zymogen and transformed into the active form by being hydrolyzed with a proteolytic enzyme such as trypsin. PLA.sub.2 -II is present in a large amount in platelets and the like, and is regarded to be mainly related to inflammation mechanisms.
Recently it was found that PLA.sub.2 -I also exists in the lung, stomach, spleen and kidney (Sakata et al., Biochim. Biophys. Acta, 1007, 124-126 (1989); Sellhamer et al., DNA, 5, 519-527 (1986); Yasuda et al., Biochim. Biophys. Acta, 1046, 189-194 (1990); and Tojo et al., J. Biol. Chem., 263, 5724-5731 (1988)). Further, it has been suggested that PLA.sub.2 -I possibly has another function other than as a digestive enzyme (Kanemasa et al., Biochim. Biophys. Acta, 1125, 210-214 (1992)). It has also been reported that PLA.sub.2 -I exhibits, through a PLA.sub.2 -I receptor, a function in the growth of cells (Arita et al., J. Biol. Chem., 266, 19139-19141 (1991)) and in contraction of lung parenchyma (Kanemasa et al., FEBS LETTERS, 303, 217-220 (1992)).
A protein which binds to PLA.sub.2 -I (i.e., a PLA.sub.2 -I receptor) was recently identified. This protein was purified from a membrane fraction of a bovine corpus luteum and comprises one glycoprotein having a molecular weight of 190,000 (Hanasaki and Arita, Biochim. Biophys. Acta, 1127, 233-241 (1992)).